Stock Marta Pads Suck
For such an expensive brakeset, Magura sure ships some crappy stock brake pads on the Marta SL set. They make so much noise and shed so much dust...my wheel hubs look just like a greasy mess. What are more quieter, less dirty replacement pads? Can I replace them myself, without bleeding them?
"Just because I drive a Porsche... doesn't make me Pete Fagerlin"
It sounds like you might have some contamination or glazing issues. If the pads and brakes are brand new and you didn't cut the lines or bleed the brakes (and got some oil on the pads) you should get in touch with Magura, they will help you out.
My experience with both the Performance and Endurance Magura compounds has been very good.
Have you bed in the brakes properly? Did you just hammer out a huge downhill and glazed the surface of the pads?
If the pads are glazed or mildly contaminated you can try sanding down the surface with wet very fine grit sandpaper and see if that gets rid of the problem.
Aside from contacting Magura, I've had success with Kool Stop pads (no noise and good power, not sure about wear though). They make pads for most brakes: Kool Stop Pads
You could try the endurance version, 6.2 for 2009 martas, 5.2 for 2008 and before. They wear a little better.
As stated above, make sure you get a good bed in on them. They will suck if you glaze them.
Lead by my Lefty............... right down the trail, no brakes.
Remember for 2009 Marta's use the Louise pads. I haven't had any issues with the Magura pads, like any pad I take them off on occasion and sand them lightly to get the crud off, keeps them quieter. Any pad on the Marta will shed dust, but if it looks greasy then you have some contamination near the calipers and most likely would need to replace pads.
First, clean them with alcohol and the sand them and see if the issue goes away, don't forgot to clean the rotors also.
I found after market brake pads on EBay. I have used them on my Martas and my Strokers. The price is definitely right.